Novel heteroleptic iridium complexe

ABSTRACT

Novel heteroleptic iridium complexes are disclosed. The complexes contain a phenyl pyridine ligand and another ligand containing a dibenzofuran, dibenzothiophene, dibenzoselenophene, or carbazole linked to an imidazole or benzimidazole fragment. These complexes are useful materials when incorporated into OLED devices.

The claimed invention was made by, on behalf of, and/or in connectionwith one or more of the following parties to a joint universitycorporation research agreement: Regents of the University of Michigan,Princeton University, The University of Southern California, and theUniversal Display Corporation. The agreement was in effect on and beforethe date the claimed invention was made, and the claimed invention wasmade as a result of activities undertaken within the scope of theagreement.

FIELD OF THE INVENTION

The present invention relates to novel heteroleptic iridium complexes,particularly complexes containing a dibenzofuran, dibenzothiophene,dibenzoselenophene, or carbazole fragment linked to an imidazole orbenzimidazole. The complexes are useful as emitters in OLED devices.

BACKGROUND

Opto-electronic devices that make use of organic materials are becomingincreasingly desirable for a number of reasons. Many of the materialsused to make such devices are relatively inexpensive, so organicopto-electronic devices have the potential for cost advantages overinorganic devices. In addition, the inherent properties of organicmaterials, such as their flexibility, may make them well suited forparticular applications such as fabrication on a flexible substrate.Examples of organic opto-electronic devices include organic lightemitting devices (OLEDs), organic phototransistors, organic photovoltaiccells, and organic photodetectors. For OLEDs, the organic materials mayhave performance advantages over conventional materials. For example,the wavelength at which an organic emissive layer emits light maygenerally be readily tuned with appropriate dopants.

OLEDs make use of thin organic films that emit light when voltage isapplied across the device. OLEDs are becoming an increasinglyinteresting technology for use in applications such as flat paneldisplays, illumination, and backlighting. Several OLED materials andconfigurations are described in U.S. Pat. Nos. 5,844,363, 6,303,238, and5,707,745, which are incorporated herein by reference in their entirety.

One application for phosphorescent emissive molecules is a full colordisplay. Industry standards for such a display call for pixels adaptedto emit particular colors, referred to as “saturated” colors. Inparticular, these standards call for saturated red, green, and bluepixels. Color may be measured using CIE coordinates, which are wellknown to the art.

One example of a green emissive molecule is tris(2-phenylpyridine)iridium, denoted Ir(ppy)₃, which has the following structure:

In this, and later figures herein, we depict the dative bond fromnitrogen to metal (here, Ir) as a straight line.

As used herein, the term “organic” includes polymeric materials as wellas small molecule organic materials that may be used to fabricateorganic opto-electronic devices. “Small molecule” refers to any organicmaterial that is not a polymer, and “small molecules” may actually bequite large. Small molecules may include repeat units in somecircumstances. For example, using a long chain alkyl group as asubstituent does not remove a molecule from the “small molecule” class.Small molecules may also be incorporated into polymers, for example as apendent group on a polymer backbone or as a part of the backbone. Smallmolecules may also serve as the core moiety of a dendrimer, whichconsists of a series of chemical shells built on the core moiety. Thecore moiety of a dendrimer may be a fluorescent or phosphorescent smallmolecule emitter. A dendrimer may be a “small molecule,” and it isbelieved that all dendrimers currently used in the field of OLEDs aresmall molecules.

As used herein, “top” means furthest away from the substrate, while“bottom” means closest to the substrate. Where a first layer isdescribed as “disposed over” a second layer, the first layer is disposedfurther away from substrate. There may be other layers between the firstand second layer, unless it is specified that the first layer is “incontact with” the second layer. For example, a cathode may be describedas “disposed over” an anode, even though there are various organiclayers in between.

As used herein, “solution processible” means capable of being dissolved,dispersed, or transported in and/or deposited from a liquid medium,either in solution or suspension form.

A ligand may be referred to as “photoactive” when it is believed thatthe ligand directly contributes to the photoactive properties of anemissive material. A ligand may be referred to as “ancillary” when it isbelieved that the ligand does not contribute to the photoactiveproperties of an emissive material, although an ancillary ligand mayalter the properties of a photoactive ligand.

As used herein, and as would be generally understood by one skilled inthe art, a first “Highest Occupied Molecular Orbital” (HOMO) or “LowestUnoccupied Molecular Orbital” (LUMO) energy level is “greater than” or“higher than” a second HOMO or LUMO energy level if the first energylevel is closer to the vacuum energy level. Since ionization potentials(IP) are measured as a negative energy relative to a vacuum level, ahigher HOMO energy level corresponds to an IP having a smaller absolutevalue (an IP that is less negative). Similarly, a higher LUMO energylevel corresponds to an electron affinity (EA) having a smaller absolutevalue (an EA that is less negative). On a conventional energy leveldiagram, with the vacuum level at the top, the LUMO energy level of amaterial is higher than the HOMO energy level of the same material. A“higher” HOMO or LUMO energy level appears closer to the top of such adiagram than a “lower” HOMO or LUMO energy level.

As used herein, and as would be generally understood by one skilled inthe art, a first work function is “greater than” or “higher than” asecond work function if the first work function has a higher absolutevalue. Because work functions are generally measured as negative numbersrelative to vacuum level, this means that a “higher” work function ismore negative. On a conventional energy level diagram, with the vacuumlevel at the top, a “higher” work function is illustrated as furtheraway from the vacuum level in the downward direction. Thus, thedefinitions of HOMO and LUMO energy levels follow a different conventionthan work functions.

More details on OLEDs, and the definitions described above, can be foundin U.S. Pat. No. 7,279,704, which is incorporated herein by reference inits entirety.

SUMMARY OF THE INVENTION

A compound having the formula:

is provided. In the compound of Formula I, R₁, R₂, and R₃ representmono-, di-, tri-, tetra-substitution or no substitution. R, R′, R₁, R₂,R₃, R₄, R₅, and R₆ are independently selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof. Any adjacent R, R′, R₁, R₂, R₃, R₄,R₅, and R₆ are optionally linked, X is selected from the groupconsisting of BR, NR, PR, O, S, Se, C═O, S═O, SO₂, CRR′, SiRR′, andGeRR′, and wherein m is 1 or 2.

In one aspect, X is selected from the group consisting of S, O, Se, andNR″; and wherein R″ is selected from the group consisting of methyl,ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, neopentyl,cyclopentyl, cyclohexyl, phenyl, 2,6-dimethylphenyl, and2,6-diiosopropylphenyl.

In one aspect, the compound has the formula:

In one aspect, the compound has the formula:

R₇ represents mono-, di-, tri-, tetra-substitution or no substitution,and wherein R₇ is selected from the group consisting of hydrogen,deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl,aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof.

In one aspect, the compound has the formula:

In one aspect, the compound has the formula:

In one aspect, m is 2. In one aspect, X is O. In one aspect, R₄ isalkyl. In one aspect, R₄ is aryl or substituted aryl.

In one aspect, R₄ is

R′₁, R′₂, and R′₃ are independently selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof. R′₃ represents mono-, di-, tri-,tetra-substitution or no substitution, and at least one of R′₁ and R′₂is not hydrogen or deuterium. Ring C is 5-membered or 6-memberedcarbocyclic or heterocyclic ring, and any adjacent R′₁, R′₂, and R′₃ maybe optionally joined to form a ring.

In one aspect, both R′₁ and R′₂ are not hydrogen or deuterium. Inanother aspect, R′₁, R′₂, and R′₃ are independently selected from thegroup consisting of hydrogen, deuterium, methyl, ethyl, isopropyl,isobutyl, neopentyl, cyclopentyl, cyclohexyl, phenyl, and combinationsthereof.

In one aspect, R₁ and R₂ are independently selected from the groupconsisting of hydrogen, deuterium, alkyl, cycloalkyl, and combinationsthereof.

In one aspect, the compound is selected from the group consisting ofCompound 1-X to Compound 30-X.

In one aspect, a first device is provided. The first device comprises afirst organic light emitting device, further comprising an anode, acathode, and an organic layer, disposed between the anode and thecathode, comprising a compound having the formula:

is provided. In the compound of Formula I, R₁, R₂, and R₃ representmono-, di-, tri-, tetra-substitution or no substitution. R, R′, R₁, R₂,R₃, R₄, R₅, and R₆ are independently selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof. Any adjacent R, R′, R₁, R₂, R₃, R₄,R₅, and R₆ are optionally linked, X is selected from the groupconsisting of BR, NR, PR, O, S, Se, C═O, S═O, SO₂, CRR′, SiRR′, andGeRR′, and wherein m is 1 or 2.

In one aspect, the first device is a consumer product. In one aspect,the first device is an organic light-emitting device. In one aspect, thefirst device comprises a lighting panel. In one aspect, the organiclayer is an emissive layer and the compound is an emissive dopant. Inanother aspect, the organic layer is an emissive layer and the compoundis a non-emissive dopant.

In one aspect, the organic layer further comprises a host. In oneaspect, the host comprises a triphenylene containing benzo-fusedthiophene or benzo-fused furan, wherein any substituent in the host isan unfused substituent independently selected from the group consistingof C_(n)H_(2n+1), OC_(n)H_(2n+1), OAr₁, N(C_(n)H_(2n+1))₂, N(Ar₁)(Ar₂),CH═CH—C_(n)H_(2n+1), C≡CHC_(n)H_(2n+1), Ar₁, Ar₁—Ar₂, C_(n)H_(2n)—Ar₁,or no substitution, wherein n is from 1 to 10, and wherein Ar₁ and Ar₂are independently selected from the group consisting of benzene,biphenyl, naphthalene, triphenylene, carbazole, and heteroaromaticanalogs thereof.

In one aspect, the host comprises one or more compounds having theformula:

wherein p is 0 or 1.

In one aspect, the host is selected from the group consisting of:

and combinations thereof. In one aspect, the host comprises a metalcomplex.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an organic light emitting device.

FIG. 2 shows an inverted organic light emitting device that does nothave a separate electron transport layer.

FIG. 3 shows a compound of Formula I.

DETAILED DESCRIPTION

Generally, an OLED comprises at least one organic layer disposed betweenand electrically connected to an anode and a cathode. When a current isapplied, the anode injects holes and the cathode injects electrons intothe organic layer(s). The injected holes and electrons each migratetoward the oppositely charged electrode. When an electron and holelocalize on the same molecule, an “exciton,” which is a localizedelectron-hole pair having an excited energy state, is formed. Light isemitted when the exciton relaxes via a photoemissive mechanism. In somecases, the exciton may be localized on an excimer or an exciplex.Non-radiative mechanisms, such as thermal relaxation, may also occur,but are generally considered undesirable.

The initial OLEDs used emissive molecules that emitted light from theirsinglet states (“fluorescence”) as disclosed, for example, in U.S. Pat.No. 4,769,292, which is incorporated by reference in its entirety.Fluorescent emission generally occurs in a time frame of less than 10nanoseconds.

More recently, OLEDs having emissive materials that emit light fromtriplet states (“phosphorescence”) have been demonstrated. Baldo et al.,“Highly Efficient Phosphorescent Emission from OrganicElectroluminescent Devices,” Nature, vol. 395, 151-154, 1998;(“Baldo-I”) and Baldo et al., “Very high-efficiency green organiclight-emitting devices based on electrophosphorescence,” Appl. Phys.Lett., vol. 75, No. 3, 4-6 (1999) (“Baldo-II”), which are incorporatedby reference in their entireties. Phosphorescence is described in moredetail in U.S. Pat. No. 7,279,704 at cols. 5-6, which are incorporatedby reference.

FIG. 1 shows an organic light emitting device 100. The figures are notnecessarily drawn to scale. Device 100 may include a substrate 110, ananode 115, a hole injection layer 120, a hole transport layer 125, anelectron blocking layer 130, an emissive layer 135, a hole blockinglayer 140, an electron transport layer 145, an electron injection layer150, a protective layer 155, and a cathode 160. Cathode 160 is acompound cathode having a first conductive layer 162 and a secondconductive layer 164. Device 100 may be fabricated by depositing thelayers described, in order. The properties and functions of thesevarious layers, as well as example materials, are described in moredetail in U.S. Pat. No. 7,279,704 at cols. 6-10, which are incorporatedby reference.

More examples for each of these layers are available. For example, aflexible and transparent substrate-anode combination is disclosed inU.S. Pat. No. 5,844,363, which is incorporated by reference in itsentirety. An example of a p-doped hole transport layer is m-MTDATA dopedwith F.sub.4-TCNQ at a molar ratio of 50:1, as disclosed in U.S. PatentApplication Publication No. 2003/0230980, which is incorporated byreference in its entirety. Examples of emissive and host materials aredisclosed in U.S. Pat. No. 6,303,238 to Thompson et al., which isincorporated by reference in its entirety. An example of an n-dopedelectron transport layer is BPhen doped with Li at a molar ratio of 1:1,as disclosed in U.S. Patent Application Publication No. 2003/0230980,which is incorporated by reference in its entirety. U.S. Pat. Nos.5,703,436 and 5,707,745, which are incorporated by reference in theirentireties, disclose examples of cathodes including compound cathodeshaving a thin layer of metal such as Mg:Ag with an overlyingtransparent, electrically-conductive, sputter-deposited ITO layer. Thetheory and use of blocking layers is described in more detail in U.S.Pat. No. 6,097,147 and U.S. Patent Application Publication No.2003/0230980, which are incorporated by reference in their entireties.Examples of injection layers are provided in U.S. Patent ApplicationPublication No. 2004/0174116, which is incorporated by reference in itsentirety. A description of protective layers may be found in U.S. PatentApplication Publication No. 2004/0174116, which is incorporated byreference in its entirety.

FIG. 2 shows an inverted OLED 200. The device includes a substrate 210,a cathode 215, an emissive layer 220, a hole transport layer 225, and ananode 230. Device 200 may be fabricated by depositing the layersdescribed, in order. Because the most common OLED configuration has acathode disposed over the anode, and device 200 has cathode 215 disposedunder anode 230, device 200 may be referred to as an “inverted” OLED.Materials similar to those described with respect to device 100 may beused in the corresponding layers of device 200. FIG. 2 provides oneexample of how some layers may be omitted from the structure of device100.

The simple layered structure illustrated in FIGS. 1 and 2 is provided byway of non-limiting example, and it is understood that embodiments ofthe invention may be used in connection with a wide variety of otherstructures. The specific materials and structures described areexemplary in nature, and other materials and structures may be used.Functional OLEDs may be achieved by combining the various layersdescribed in different ways, or layers may be omitted entirely, based ondesign, performance, and cost factors. Other layers not specificallydescribed may also be included. Materials other than those specificallydescribed may be used. Although many of the examples provided hereindescribe various layers as comprising a single material, it isunderstood that combinations of materials, such as a mixture of host anddopant, or more generally a mixture, may be used. Also, the layers mayhave various sublayers. The names given to the various layers herein arenot intended to be strictly limiting. For example, in device 200, holetransport layer 225 transports holes and injects holes into emissivelayer 220, and may be described as a hole transport layer or a holeinjection layer. In one embodiment, an OLED may be described as havingan “organic layer” disposed between a cathode and an anode. This organiclayer may comprise a single layer, or may further comprise multiplelayers of different organic materials as described, for example, withrespect to FIGS. 1 and 2.

Structures and materials not specifically described may also be used,such as OLEDs comprised of polymeric materials (PLEDs) such as disclosedin U.S. Pat. No. 5,247,190 to Friend et al., which is incorporated byreference in its entirety. By way of further example, OLEDs having asingle organic layer may be used. OLEDs may be stacked, for example asdescribed in U.S. Pat. No. 5,707,745 to Forrest et al, which isincorporated by reference in its entirety. The OLED structure maydeviate from the simple layered structure illustrated in FIGS. 1 and 2.For example, the substrate may include an angled reflective surface toimprove out-coupling, such as a mesa structure as described in U.S. Pat.No. 6,091,195 to Forrest et al., and/or a pit structure as described inU.S. Pat. No. 5,834,893 to Bulovic et al., which are incorporated byreference in their entireties.

Unless otherwise specified, any of the layers of the various embodimentsmay be deposited by any suitable method. For the organic layers,preferred methods include thermal evaporation, ink-jet, such asdescribed in U.S. Pat. Nos. 6,013,982 and 6,087,196, which areincorporated by reference in their entireties, organic vapor phasedeposition (OVPD), such as described in U.S. Pat. No. 6,337,102 toForrest et al., which is incorporated by reference in its entirety, anddeposition by organic vapor jet printing (OVJP), such as described inU.S. patent application Ser. No. 10/233,470, which is incorporated byreference in its entirety. Other suitable deposition methods includespin coating and other solution based processes. Solution basedprocesses are preferably carried out in nitrogen or an inert atmosphere.For the other layers, preferred methods include thermal evaporation.Preferred patterning methods include deposition through a mask, coldwelding such as described in U.S. Pat. Nos. 6,294,398 and 6,468,819,which are incorporated by reference in their entireties, and patterningassociated with some of the deposition methods such as ink-jet and OVJD.Other methods may also be used. The materials to be deposited may bemodified to make them compatible with a particular deposition method.For example, substituents such as alkyl and aryl groups, branched orunbranched, and preferably containing at least 3 carbons, may be used insmall molecules to enhance their ability to undergo solution processing.Substituents having 20 carbons or more may be used, and 3-20 carbons isa preferred range. Materials with asymmetric structures may have bettersolution processibility than those having symmetric structures, becauseasymmetric materials may have a lower tendency to recrystallize.Dendrimer substituents may be used to enhance the ability of smallmolecules to undergo solution processing.

Devices fabricated in accordance with embodiments of the invention maybe incorporated into a wide variety of consumer products, including flatpanel displays, computer monitors, medical monitors, televisions,billboards, lights for interior or exterior illumination and/orsignaling, heads up displays, fully transparent displays, flexibledisplays, laser printers, telephones, cell phones, personal digitalassistants (PDAs), laptop computers, digital cameras, camcorders,viewfinders, micro-displays, vehicles, a large area wall, theater orstadium screen, or a sign. Various control mechanisms may be used tocontrol devices fabricated in accordance with the present invention,including passive matrix and active matrix. Many of the devices areintended for use in a temperature range comfortable to humans, such as18 degrees C. to 30 degrees C., and more preferably at room temperature(20-25 degrees C.).

The materials and structures described herein may have applications indevices other than OLEDs. For example, other optoelectronic devices suchas organic solar cells and organic photodetectors may employ thematerials and structures. More generally, organic devices, such asorganic transistors, may employ the materials and structures.

The terms halo, halogen, alkyl, cycloalkyl, alkenyl, alkynyl, arylkyl,heterocyclic group, aryl, aromatic group, and heteroaryl are known tothe art, and are defined in U.S. Pat. No. 7,279,704 at cols. 31-32,which are incorporated herein by reference.

A compound having the formula:

is provided. In the compound of Formula I, R₁, R₂, and R₃ representmono-, di-, tri-, tetra-substitution or no substitution. R, R′, R₁, R₂,R₃, R₄, R₅, and R₆ are independently selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof. Any adjacent R, R′, R₁, R₂, R₃, R₄,R₅, and R₆ are optionally linked, X is selected from the groupconsisting of BR, NR, PR, O, S, Se, C═O, S═O, SO₂, CRR′, SiRR′, andGeRR′, and wherein m is 1 or 2.

It has been unexpectedly discovered that combining ppy(2-phenylpyridine) and DBX-imidazole or DBX-benzimidazole ligands toform heteroleptic iridium complexes not known in literature results incompounds with superior properties. The term DBX refers to the structureshown below, where X can be any of the atoms or groups disclosed herein,and where the DBX ring may be further substituted as also disclosedherein.

Thus, for example, DBT is dibenzothiophene (X═S), and DBF isdibenzofuran (X═O). Compounds of Formula I, when incorporated into OLEDdevices can result in devices with improved efficiency and lifetimes.The compounds of Formula I can be tuned to emit a more saturated greencolor.

In one embodiment, X is selected from the group consisting of S, O, Se,and NR″; and wherein R″ is selected from the group consisting of methyl,ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, neopentyl,cyclopentyl, cyclohexyl, phenyl, 2,6-dimethylphenyl, and2,6-diiosopropylphenyl.

In one embodiment, the compound has the formula:

In one embodiment, the compound has the formula:

R₇ represents mono-, di-, tri-, tetra-substitution or no substitution,and wherein R₇ is selected from the group consisting of hydrogen,deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy,aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl,aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof.

In one embodiment, the compound has the formula:

In one embodiment, the compound has the formula:

In one embodiment, m is 2. In one embodiment, X is O. In one embodiment,R₄ is alkyl. In one embodiment, R₄ is aryl or substituted aryl.

In one embodiment, R₄ is

R′₁, R′₂, and R′₃ are independently selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof. R′₃ represents mono-, di-, tri-,tetra-substitution or no substitution, and at least one of R′₁ and R′₂is not hydrogen or deuterium. Ring C is 5-membered or 6-memberedcarbocyclic or heterocyclic ring, and any adjacent R′₁, R′₂, and R′₃ maybe optionally joined to form a ring.

In one embodiment, both R′₁ and R′₂ are not hydrogen or deuterium. Inanother aspect, R′₁, R′₂, and R′₃ are independently selected from thegroup consisting of hydrogen, deuterium, methyl, ethyl, isopropyl,isobutyl, neopentyl, cyclopentyl, cyclohexyl, phenyl, and combinationsthereof.

In one embodiment, R₁ and R₂ are independently selected from the groupconsisting of hydrogen, deuterium, alkyl, cycloalkyl, and combinationsthereof.

In one embodiment, the compound is selected from the group consistingof:

Compounds 1-X to 30-X represent compounds where X may represent atoms orgroups as disclosed herein. When X is a specific atom, the name of thatparticular compound corresponds to the nature of the X atom. Thus, whenX═O, Compound 1-X is called Compound 1-O, and when X═S, Compound 1-X iscalled Compound 1-S, etc. The same naming scheme can be used for any ofthe other compounds described above.

In one embodiment, a first device is provided. The first devicecomprises a first organic light emitting device, further comprising ananode, a cathode, and an organic layer, disposed between the anode andthe cathode, comprising a compound having the formula:

is provided. In the compound of Formula I, R₁, R₂, and R₃ representmono-, di-, tri-, tetra-substitution or no substitution. R, R′. R₁, R₂,R₃, R₄, R₅, and R₆ are independently selected from the group consistingof hydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl,arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl,heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylicacids, ester, nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl,phosphino, and combinations thereof. Any adjacent R, R′, R₁, R₂, R₃, R₄,R₅, and R₆ are optionally linked, X is selected from the groupconsisting of BR, NR, PR, O, S, Se, C═O, S═O, SO₂, CRR′, SiRR′, andGeRR′, and wherein m is 1 or 2. In one embodiment, X is selected fromthe group consisting of BR, NR, PR, O, S, Se, C═O, S═O, SO₂, CRR′,SiRR′, and GeRR′.

In one embodiment, the first device is a consumer product. In oneembodiment, the first device is an organic light-emitting device. In oneembodiment, the first device comprises a lighting panel. In oneembodiment, the organic layer is an emissive layer and the compound isan emissive dopant. In another embodiment, the organic layer is anemissive layer and the compound is a non-emissive dopant.

In one embodiment, the organic layer further comprises a host. In oneembodiment, the host comprises a triphenylene containing benzo-fusedthiophene or benzo-fused furan, wherein any substituent in the host isan unfused substituent independently selected from the group consistingof C_(n)H_(2n+1), OC_(n)H_(2n+1), OAr₁, N(C_(n)H_(2n+1))₂, N(Ar₁)(Ar₂),CH═CH—C_(n)H_(2n+1), C≡CHC_(n)H_(2n+1), Ar₁, Ar₁—Ar₂, C_(n)H_(2n)—Ar₁,or no substitution, wherein n is from 1 to 10, and wherein Ar₁ and Ar₂are independently selected from the group consisting of benzene,biphenyl, naphthalene, triphenylene, carbazole, and heteroaromaticanalogs thereof.

In one embodiment, the host comprises one or more compounds having theformula:

wherein p is 0 or 1.

In one embodiment, the host is selected from the group consisting of:

and combinations thereof. In one embodiment, the host comprises a metalcomplex.

Device Examples

All example devices were fabricated by high vacuum (<10⁻⁷ Torr) thermalevaporation. The anode electrode is 1200 Å of indium tin oxide (ITO).The cathode consisted of 10 Å of LiF followed by 1,000 Å of Al. Alldevices are encapsulated with a glass lid sealed with an epoxy resin ina nitrogen glove box (<1 ppm of H₂O and O₂) immediately afterfabrication, and a moisture getter was incorporated inside the package.

The organic stack of the device examples consisted of sequentially, fromthe ITO surface, 100 Å of Compound B or C as the hole injection layer(HIL), 300 Å of 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (NPD) asthe hole transporting layer (HTL), 300 Å of the invention compound dopedin compound D as host with 7, 10, 13 wt % of a compound of Formula I asthe emissive layer (EML), 50 A of the compound D as block layer (BL),450 Å of Alq₃ (tris-8-hydroxyquinoline aluminum) as the ETL. ComparativeExamples with compound A or E was fabricated similarly to the DeviceExamples except that the compound A or E is used as the emitter in theEML.

The device structure and data are summarized in Table 1 and Table 2 fromthose devices. As used herein, Compounds A, B, C, D and E have thefollowing structures:

TABLE 1 Device Structures of Invention Compounds and ComparativeCompound A and B Example HIL HTL EML (300 A, doping %) BL ETLComparative Compound C NPD 300 Å Compound D Compound A Compound D Alq450 Å Example 1 100 Å  7% 50 Å Comparative Compound C NPD 300 Å CompoundD Compound A Compound D Alq 450 Å Example 2 100 Å 10% 50 Å ComparativeCompound C NPD 300 Å Compound D Compound A Compound D Alq 450 Å Example3 100 Å 13% 50 Å Comparative Compound C NPD 300 Å Compound D Compound ECompound D Alq 450 Å Example 4 100 Å  7% 50 Å Comparative Compound C NPD300 Å Compound D Compound E Compound D Alq 450 Å Example 5 100 Å 10% 50Å Example 1 Compound B NPD 300 Å Compound D Compound 1 Compound D Alq450 Å 100 Å  7% 50 Å Example 2 Compound B NPD 300 Å Compound D Compound1 Compound D Alq 450 Å 100 Å 10% 50 Å

TABLE 2 VTE Device Data of Invention Compounds and Comparative Compoundsλ_(max) FWHM Voltage LE EQE PE LT80% x y (nm) (nm) (V) (Cd/A) (%) (lm/W)(h) Comparative 0.359 0.611 530 66 6.5 59.4 15.9 28.8 169 Example 1Compound A Comparative 0.363 0.609 530 66 6.1 57.3 15.4 29.4 177 Example2 Compound A Comparative 0.364 0.608 530 66 6.1 52.6 14.1 27.0 168Example 3 Compound A Comparative 0.320 0.622 519 71 6.1 50.4 14 26.1 200Example 4 Compound E Comparative 0.325 0.620 519 72 5.7 50.5 14 27.6 270Example 5 Compound E Example 1 0.372 0.601 528 68 6.2 62.4 17.1 31.4219.3 Compound 1-O Example 2 0.372 0.602 528 66 5.5 70.7 19.3 40.6 248.0Compound 1-O

Table 2 is a summary of the device data. The luminous efficiency (LE),external quantum efficiency (EQE) and power efficiency (PE) weremeasured at 1000 nits, while the lifetime (LT_(80%)) was defined as thetime required for the device to decay to 80% of its initial luminanceunder a constant current density of 40 mA/cm².

From Table 2 it can be seen that the external quantum efficiency EQE(19.3%), luminous efficiency LE (70.7 Cd/A), lifetime at 80% LT₈₀% (248hours) and power efficiency PE (40.6 lm/W) of compounds of Formula I,such as Compound 1-O, at a doping concentration of 10% (Example 2) areall higher than the corresponding Comparative Compounds A to E(Comparative Examples 1 to 5) at all three doping concentration 7%, 10%and 13% except the lifetime of Comparative Example 5 LT₈₀% (270 hours).Similarly higher EQE, LE, LT_(80%) and PE of Compound 1-O at a lowerdoping concentration of 7% (Example 1) can be found when compared withcomparative Compound A to E (Comparative Examples 1 to 5). These dataclearly demonstrated that compounds of Formula I, such as Compound 1-Ois more efficient and longer-lived emitter than comparative compounds Aand E.

Combination with Other Materials

The materials described herein as useful for a particular layer in anorganic light emitting device may be used in combination with a widevariety of other materials present in the device. For example, emissivedopants disclosed herein may be used in conjunction with a wide varietyof hosts, transport layers, blocking layers, injection layers,electrodes and other layers that may be present. The materials describedor referred to below are non-limiting examples of materials that may beuseful in combination with the compounds disclosed herein, and one ofskill in the art can readily consult the literature to identify othermaterials that may be useful in combination.

HIL/HTL:

A hole injecting/transporting material to be used in the presentinvention is not particularly limited, and any compound may be used aslong as the compound is typically used as a hole injecting/transportingmaterial. Examples of the material include, but not limit to: aphthalocyanine or porphryin derivative; an aromatic amine derivative; anindolocarbazole derivative; a polymer containing fluorohydrocarbon; apolymer with conductivity dopants; a conducting polymer, such asPEDOT/PSS; a self-assembly monomer derived from compounds such asphosphonic acid and sliane derivatives; a metal oxide derivative, suchas MoO_(x); a p-type semiconducting organic compound, such as1,4,5,8,9,12-Hexaazatriphenylenehexacarbonitrile; a metal complex, and across-linkable compounds.

Examples of aromatic amine derivatives used in HIL or HTL include, butnot limit to the following general structures:

Each of Ar¹ to Ar⁹ is selected from the group consisting aromatichydrocarbon cyclic compounds such as benzene, biphenyl, triphenyl,triphenylene, naphthalene, anthracene, phenalene, phenanthrene,fluorene, pyrene, chrysene, perylene, azulene; group consisting aromaticheterocyclic compounds such as dibenzothiophene, dibenzofuran,dibenzoselenophene, furan, thiophene, benzofuran, benzothiophene,benzoselenophene, carbazole, indolocarbazole, pyridylindole,pyrrolodipyridine, pyrazole, imidazole, triazole, oxazole, thiazole,oxadiazole, oxatriazole, dioxazole, thiadiazole, pyridine, pyridazine,pyrimidine, pyrazine, triazine, oxazine, oxathiazine, oxadiazine,indole, benzimidazole, indazole, indoxazine, benzoxazole, benzisoxazole,benzothiazole, quinoline, isoquinoline, cinnoline, quinazoline,quinoxaline, naphthyridine, phthalazine, pteridine, xanthene, acridine,phenazine, phenothiazine, phenoxazine, benzofuropyridine,furodipyridine, benzothienopyridine, thienodipyridine,benzoselenophenopyridine, and selenophenodipyridine; and groupconsisting 2 to 10 cyclic structural units which are groups of the sametype or different types selected from the aromatic hydrocarbon cyclicgroup and the aromatic heterocyclic group and are bonded to each otherdirectly or via at least one of oxygen atom, nitrogen atom, sulfur atom,silicon atom, phosphorus atom, boron atom, chain structural unit and thealiphatic cyclic group. Wherein each Ar is further substituted by asubstituent selected from the group consisting of hydrogen, deuterium,halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfonyl, sulfonyl, phosphino, and combinationsthereof.

In one aspect, Ar¹ to Ar⁹ is independently selected from the groupconsisting of

k is an integer from 1 to 20; X¹ to X⁸ is C (including CH) or N; Ar¹ hasthe same group defined above.

Examples of metal complexes used in HIL or HTL include, but not limit tothe following general formula:

M is a metal, having an atomic weight greater than 40; (Y¹—Y²) is abidentate ligand, Y¹ and Y² are independently selected from C, N, O, P,and S; L is an ancillary ligand; m is an integer value from 1 to themaximum number of ligands that may be attached to the metal; and m+n isthe maximum number of ligands that may be attached to the metal.

In one aspect, (Y¹—Y²) is a 2-phenylpyridine derivative.

In another aspect, (Y¹—Y²) is a carbene ligand.

In another aspect, M is selected from Ir, Pt, Os, and Zn.

In a further aspect, the metal complex has a smallest oxidationpotential in solution vs. Fc⁺/Fc couple less than about 0.6 V.

Host:

The light emitting layer of the organic EL device of the presentinvention preferably contains at least a metal complex as light emittingmaterial, and may contain a host material using the metal complex as adopant material. Examples of the host material are not particularlylimited, and any metal complexes or organic compounds may be used aslong as the triplet energy of the host is larger than that of thedopant. While the Table below categorizes host materials as preferredfor devices that emit various colors, any host material may be used withany dopant so long as the triplet criteria is satisfied.

Examples of metal complexes used as host are preferred to have thefollowing general formula:

M is a metal; (Y³—Y⁴) is a bidentate ligand, Y³ and Y⁴ are independentlyselected from C, N, O, P, and S; L is an ancillary ligand; m is aninteger value from 1 to the maximum number of ligands that may beattached to the metal; and m+n is the maximum number of ligands that maybe attached to the metal.

In one aspect, the metal complexes are:

(O—N) is a bidentate ligand, having metal coordinated to atoms O and N.

In another aspect, M is selected from Ir and Pt.

In a further aspect, (Y³—Y⁴) is a carbene ligand.

Examples of organic compounds used as host are selected from the groupconsisting aromatic hydrocarbon cyclic compounds such as benzene,biphenyl, triphenyl, triphenylene, naphthalene, anthracene, phenalene,phenanthrene, fluorene, pyrene, chrysene, perylene, azulene; groupconsisting aromatic heterocyclic compounds such as dibenzothiophene,dibenzofuran, dibenzoselenophene, furan, thiophene, benzofuran,benzothiophene, benzoselenophene, carbazole, indolocarbazole,pyridylindole, pyrrolodipyridine, pyrazole, imidazole, triazole,oxazole, thiazole, oxadiazole, oxatriazole, dioxazole, thiadiazole,pyridine, pyridazine, pyrimidine, pyrazine, triazine, oxazine,oxathiazine, oxadiazine, indole, benzimidazole, indazole, indoxazine,benzoxazole, benzisoxazole, benzothiazole, quinoline, isoquinoline,cinnoline, quinazoline, quinoxaline, naphthyridine, phthalazine,pteridine, xanthene, acridine, phenazine, phenothiazine, phenoxazine,benzofuropyridine, furodipyridine, benzothienopyridine,thienodipyridine, benzoselenophenopyridine, and selenophenodipyridine;and group consisting 2 to 10 cyclic structural units which are groups ofthe same type or different types selected from the aromatic hydrocarboncyclic group and the aromatic heterocyclic group and are bonded to eachother directly or via at least one of oxygen atom, nitrogen atom, sulfuratom, silicon atom, phosphorus atom, boron atom, chain structural unitand the aliphatic cyclic group. Wherein each group is furthersubstituted by a substituent selected from the group consisting ofhydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.

In one aspect, host compound contains at least one of the followinggroups in the molecule:

R¹ to R⁷ is independently selected from the group consisting ofhydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof, when it is aryl or heteroaryl, it has the similardefinition as Ar's mentioned above.

k is an integer from 0 to 20.

X¹ to X⁸ is selected from C (including CH) or N.

Z¹ and Z² is selected from NR¹, O, or S.

HBL:

A hole blocking layer (HBL) may be used to reduce the number of holesand/or excitons that leave the emissive layer. The presence of such ablocking layer in a device may result in substantially higherefficiencies as compared to a similar device lacking a blocking layer.Also, a blocking layer may be used to confine emission to a desiredregion of an OLED.

In one aspect, compound used in HBL contains the same molecule or thesame functional groups used as host described above.

In another aspect, compound used in HBL contains at least one of thefollowing groups in the molecule:

k is an integer from 0 to 20; L is an ancillary ligand, m is an integerfrom 1 to 3.

ETL:

Electron transport layer (ETL) may include a material capable oftransporting electrons. Electron transport layer may be intrinsic(undoped), or doped. Doping may be used to enhance conductivity.Examples of the ETL material are not particularly limited, and any metalcomplexes or organic compounds may be used as long as they are typicallyused to transport electrons.

In one aspect, compound used in ETL contains at least one of thefollowing groups in the molecule:

R¹ is selected from the group consisting of hydrogen, deuterium, halide,alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy, amino,silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl,acyl, carbonyl, carboxylic acids, ester, nitrile, isonitrile, sulfanyl,sulfinyl, sulfonyl, phosphino, and combinations thereof, when it is arylor heteroaryl, it has the similar definition as Ar's mentioned above.

Ar¹ to Ar³ has the similar definition as Ar's mentioned above.

k is an integer from 0 to 20.

X¹ to X⁸ is selected from C (including CH) or N.

In another aspect, the metal complexes used in ETL contains, but notlimit to the following general formula:

(O—N) or (N—N) is a bidentate ligand, having metal coordinated to atomsO, N or N, N; L is an ancillary ligand; m is an integer value from 1 tothe maximum number of ligands that may be attached to the metal.

In any above-mentioned compounds used in each layer of the OLED device,the hydrogen atoms can be partially or fully deuterated.

In addition to and/or in combination with the materials disclosedherein, many hole injection materials, hole transporting materials, hostmaterials, dopant materials, exiton/hole blocking layer materials,electron transporting and electron injecting materials may be used in anOLED. Non-limiting examples of the materials that may be used in an OLEDin combination with materials disclosed herein are listed in Table 3below. Table 3 lists non-limiting classes of materials, non-limitingexamples of compounds for each class, and references that disclose thematerials.

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Experimental

Chemical abbreviations used throughout this document are as follows: Cyis cyclohexyl, dba is dibenzylideneacetone, EtOAc is ethyl acetate, DMEis dimethoxyethane, dppe is 1,2-bis(diphenylphosphino)ethane, dppf is1,1′-Bis(diphenylphosphino)ferrocene, THF is tetrahydrofuran, DCM isdichloromethane, S-Phos isdicyclohexyl(2′,6′-dimethoxy-[1,1′-biphenyl]-2-yl)phosphine.

Synthesis of Compound 1-O

Synthesis of 2,6-diisopropyl-N-(2-nitrophenyl)aniline

1-Bromo-2-nitrobenzene (15 g, 75 mmol), 2,6-diisopropylaniline (14.0 mL,75 mmol) and cesium carbonate (41.5 g, 127 mmol) were mixed in 500 mL oftoluene and the solution was bubbled with nitrogen for 20 minutes.Pd₂(dba)₃ (1.36 g, 1.49 mmol) anddicyclohexyl(2′,6′-dimethoxy-[1,1′-biphenyl]-2-yl)phosphine (2.44 g,5.94 mmol) were added and reaction mixture was heated to reflux for 18hours. After cooling, the organic layer separated and the aqueous layerwas extracted with 3×50 mL dichloromethane and dried over sodiumsulfate. After removing the solvent under reduced pressure, the crudeproduct was chromatographed on silica gel with 10:90 ethylacetate:hexane (v/v) and 20 g (72%) of the product was obtained. Theproduct was confirmed by GC/MS, NMR and HPLC (99.96% pure)

Synthesis of N-(2,6-diisopropylphenyl)benzene-1,2-diamine

Diisopropyl-N-(2-nitrophenyl) aniline (12 g, 40.2 mmol) was dissolved in200 mL ethanol and palladium on carbon (0.642 g) was added. The reactionmixture was placed on the Parr hydrogenator for 1 hour. The reactionmixture was filtered through a Celite® plug, washed with dichloromethaneand evaporated. The crude product was chromatographed on silica gel with10:90 ethyl acetate:hexane (v/v) and 10 g (93%) of the product wasobtained. The product was confirmed by GC/MS and NMR.

Synthesis of benzo[b,d]furan-4-carbaldehyde

A 1 L round bottom flask was charged with 2,4-dibenzo[b,d]furan (24 g,143 mmol) in 300 mL THF, cooled to −78° C. Butyl lithium (98 mL, 157mmol) was added very slowly. The reaction was warmed up to roomtemperature for five hours. The reaction was cooled back to −78° C.N,N-dimethylformamide (14.36 mL, 186 mmol) was dissolved in 50 mL THFand added very slowly over the reaction. The reaction was warmed up toroom temperature overnight. 300 mL of brine was added to the reaction.After separation of the layers, the aqueous layer was extracted withethyl acetate (2×100 mL). After removal of the solvent, the crudeproduct was subjected to column chromatography (SiO₂, 10% ethyl acetateand 10% DCM in hexane), then crystallized from hexane to get 14 g(50.2%) purified product.

Synthesis of2-(dibenzo[b,d]furan-4-yl)-1-(2,6-diisopropylphenyl)-1-H-benzo[d]imidazole

N-(2,6-diisopropylphenyl)benzene-1,2-diamine (4.5 g, 16.77 mmol),dibenzo[b,d]furan-4-carbldehyde (4.93 g, 25.1 mmol) and1-hexadecylpyridinium bromide (0.322 g, 0.838 mmol) were dissolved in 10mL THF and 200 mL water and stirred at room temperature overnight. GC/MSanalysis of the reaction mixture typically showed the presence of amixture of the phenylbenzimidazole product and thephenyl-2,3-dihydro-1H-benzo[d]imidazole product (ca. 50:50). Brine (200mL) was added and the reaction mixture which was extracted with EtOAc(3×300 mL), dried over sodium sulfate and evaporated. The total crudeyield was 7 g (94%) and the product was carried onto the next stepwithout further purification.

Synthesis of2-(dibenzo[b,d]furan-4-yl)-1-(2,6-diisopropylphenyl)-1-H-benzo[d]imidazole

The mixture of the dibenzofuranbenzimidazole product and thedibenzofuran-2,3-dihydro-1H-benzo[d]imidazole product (7 g, 15.67 mmol)from the previous step was combined and manganese(IV) oxide (13.6 g, 156mmol) in 100 mL of toluene. With vigorous stirring, the reaction washeated to reflux for 16 hours, cooled, filtered through a plug of silicagel eluted with dichloromethane and evaporated. The crude product waschromatographed on silica gel with 0-3% ethyl acetate in dichloromethaneand then recrystallized from hexane to give 4.3 g (61.7%) of theproduct. The product was confirmed by HPLC and NMR.

Synthesis of Compound 1-O

A mixture of iridium trifluormethanesulfonate complex (2.0 g, 2.75 mmol2-(dibenzo[b,d]furan-4-yl)-1-(2,6-diisopropylphenyl)-1H-benzo[d]imidazole(3.67 g, 8.24 mmol) in EtOH (25 mL) and MeOH (25 mL) was refluxed for 20hours under nitrogen atmosphere. The reaction mixture was cooled back toroom temperature, diluted with ethanol and Celite® was added and themixture stirred for 10 minutes. The mixture was filtered on a smallsilica gel plug and washed with ethanol (3-4 times) and with hexane (3-4times). The filtrate was discarded. The Celite®/silica plug was thenwashed with dichloromethane to elute the product. The crude product waschromatographed on silica gel with 30% DCM/hexane. The product waschromatographed again on silica gel eluting with 20-30% THF in hexane.0.32 g (12.5%) of Compound I-0 was obtained after sublimation, which wasconfirmed by LC-MS.

Synthesis of Compound 12-O

Synthesis of 4-iodobenzo[b,d]furan

A 1 L round bottom flask was charged with 2,4-dibenzo[b,d]furan (25 g,149 mmol) in 300 mL of THF and cooled to −78° C. n-Butyl lithium (102mL, 164 mmol) was added slowly. The reaction was warmed up to roomtemperature for five hours. The reaction was cooled back to −78° C.Iodine (37.7 g, 149 mmol) was dissolved in 50 mL of THF and added slowlyto the reaction. The reaction was warmed up to room temperatureovernight. 300 mL of aqueous sodium bicarbonate was added to thereaction. After separation of the layers, the aqueous layer wasextracted with ethyl acetate (2×100 mL). After removal of the solvent,the crude product was subjected to column chromatography (SiO₂, 3% ethylacetate in hexane), then crystallized from hexane to get 30 g pureproduct (70%).

Synthesis of dibenzo-[b,d]furan-4-carbonitrile

4-Iododibenzo-[b,d]furan (11.5 g, 39.1 mmol)1,1′-Bis(diphenylphosphino)ferrocene (dppf) (0.867 g, 1.564 mmol),dicyanozinc (2.75 g, 23.46 mmol), 10% Pd/C (0.416 g, 0.391 mmol) and 100mL of dimethylacetamide (DMAC) were placed in 3 neck flask. Nitrogen wasbubbled for 10 minutes. Bis-(formyloxy) zinc (0.608 g, 3.91 mmol) wasadded to the reaction and degassed with nitrogen again for 10 minutes,then heated to 105° C. under nitrogen for 3 hours. The reaction wascooled down to room temperature diluted with 100 mL ethyl acetate. Thisreaction mixture was filtered and washed with ethyl acetate. The organiclayer washed with 2×100 mL water and 1×100 mL 5% NH₄OH. The crudeproduct was subject to chromatography, eluting with 5% ethyl acetate inhexane to obtain 5.2 g (68.8%) of purified product.

Synthesis of1-(2,6-diisopropylphenyl)dibenzo[b,d]-3-yl)furan-4-carboximidamide

Trimethylaluminum (10.35 mL, 20.7 mmol) was added slowly into2,6-diisopropylaniline (3.90 mL, 20.70 mmol) in 100 mL toluene at 0° C.under nitrogen. The reaction was allowed to stir at room temperature for2 hours. N-(2,6-diisopropylphenyl)dibenzo[b,d]furan-4-carboximidamide in50 mL toluene was added to the reaction and heated to 70° C. overnight.The reaction was cooled down with ice bath and poured into a stirringslurry silica gel in 2:1 DCM/methanol (v/v) and filtered and washed withDCM and methanol. After solvent evaporation, the solid was trituratedwith hexane to give 5.5 g (71.7%) of product.

Synthesis of2-(dibenzo[b,d]-3-yl)furan-4-yl)-1-(2,6-diisopropylphenyl)-1H-imidazole

N-(2,6-diisopropylphenyl)dibenzo[b,d]furan-4-carboximidamide (7 g, 18.89mmol), chloroacetaldehyde (4.80 mL, 37.8 mmol) and sodium bicarbonate(3.17 g, 37.8 mmol) in 100 mL of 2-propanol was heated up to reflux for3 hours under nitrogen. The reaction was cooled to room temperature anddiluted with 100 mL water and 100 mL ethyl acetate. The mixture wasseparated on an alumina (Al₂O₃) column, eluting with DCM/methanol 0-10%,to obtain 3.05 g (51.2%) of pure product.

Synthesis of Compound 12-O

A mixture of iridium trifluormethanesulfonate complex (1.6 g, 2.04 mmol)and 2-(dibenzo[b,d]furan-4-yl)-1-(2,6-diisopropylphenyl)-1H-imidazole(2.013 g, 5.10 mmol) in EtOH (25 mL) and MeOH (25 mL) was refluxed for20 hours under nitrogen atmosphere. The reaction mixture was cooled toroom temperature and diluted with ethanol. Celite® was added to themixture with stirring for 10 minutes. The mixture was filtered on asmall silica gel plug and washed with ethanol (3-4 times) and hexane(3-4 times). The Celite®/silica plug was then washed withdichloromethane until no more material came through. The DCM filtratewas evaporated and run a reverse silica column to obtain 0.85 g (43.8%)of product, which was confirmed by LC-MS.

It is understood that the various embodiments described herein are byway of example only, and are not intended to limit the scope of theinvention. For example, many of the materials and structures describedherein may be substituted with other materials and structures withoutdeviating from the spirit of the invention. The present invention asclaimed may therefore include variations from the particular examplesand preferred embodiments described herein, as will be apparent to oneof skill in the art. It is understood that various theories as to whythe invention works are not intended to be limiting.

1. A compound having the formula:

wherein R₁, R₂, and R₃ represent mono-, di-, tri-, tetra-substitution orno substitution; wherein R, R′, R₁, R₂, R₃, R₄, R₅, and R₆ areindependently selected from the group consisting of hydrogen, deuterium,halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof; wherein any adjacent R, R′, R₁, R₂, R₃, R₄, R₅, and R₆ areoptionally linked; wherein X is selected from the group consisting ofBR, NR, PR, O, S, Se, C═O, S═O, SO₂, CRR′, SiRR′, and GeRR′; and whereinm is 1 or
 2. 2. The compound of claim 1, wherein X is selected from thegroup consisting of O, S, Se, and NR″; and wherein R″ is selected fromthe group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, neopentyl, cyclopentyl, cyclohexyl, phenyl,2,6-dimethylphenyl, and 2,6-diiosopropylphenyl.
 3. The compound of claim2, wherein the compound has the formula:


4. The compound of claim 2, wherein the compound has the formula:

wherein R₇ represents mono-, di-, tri-, tetra-substitution or nosubstitution, and wherein R₇ is selected from the group consisting ofhydrogen, deuterium, halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl,alkoxy, aryloxy, amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl,alkynyl, aryl, heteroaryl, acyl, carbonyl, carboxylic acids, ester,nitrile, isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, andcombinations thereof.
 5. The compound of claim 4, wherein the compoundhas the formula:


6. The compound of claim 5, wherein the compound has the formula:


7. The compound of claim 2, wherein m is
 2. 8. The compound of claim 2,wherein X is O.
 9. The compound of claim 2, wherein R₄ is alkyl.
 10. Thecompound of claim 2, wherein R₄ is aryl or substituted aryl.
 11. Thecompound of claim 10, wherein R₄ is

wherein R′₁, R′₂, and R′₃ are independently selected from the groupconsisting of hydrogen, deuterium, halide, alkyl, cycloalkyl,heteroalkyl, arylalkyl, alkoxy, aryloxy, amino, silyl, alkenyl,cycloalkenyl, heteroalkenyl, alkynyl, aryl, heteroaryl, acyl, carbonyl,carboxylic acids, ester, nitrile, isonitrile, sulfanyl, sulfinyl,sulfonyl, phosphino, and combinations thereof; wherein R′₃ representsmono-, di-, tri-, tetra-substitution or no substitution; wherein atleast one of R′₁ and R′₂ is not hydrogen or deuterium; and wherein ringC is 5-membered or 6-membered carbocyclic or heterocyclic ring; andwherein any adjacent R′₁, R′₂, and R′₃ may be optionally joined to forma ring.
 12. The compound of claim 11, wherein both R′, and R′₂ are nothydrogen or deuterium.
 13. The compound of claim 11, wherein R′₁, R′₂,and R′₃ are independently selected from the group consisting ofhydrogen, deuterium, methyl, ethyl, isopropyl, isobutyl, neopentyl,cyclopentyl, cyclohexyl, phenyl, and combinations thereof.
 14. Thecompound of claim 2, wherein R₁ and R₂ are independently selected fromthe group consisting of hydrogen, deuterium, alkyl, cycloalkyl, andcombinations thereof.
 15. The compound of claim 2, wherein the compoundis selected from the group consisting of:


16. A first device comprising a first organic light emitting device,further comprising: an anode; a cathode; and an organic layer, disposedbetween the anode and the cathode, comprising a compound having theformula:

wherein R₁, R₂, and R₃ represent mono-, di-, tri-, tetra-substitution orno substitution; wherein R, R′, R₁, R₂, R₃, R₄, R₅, and R₆ areindependently selected from the group consisting of hydrogen, deuterium,halide, alkyl, cycloalkyl, heteroalkyl, arylalkyl, alkoxy, aryloxy,amino, silyl, alkenyl, cycloalkenyl, heteroalkenyl, alkynyl, aryl,heteroaryl, acyl, carbonyl, carboxylic acids, ester, nitrile,isonitrile, sulfanyl, sulfinyl, sulfonyl, phosphino, and combinationsthereof; wherein any adjacent R, R′, R₁, R₂, R₃, R₄, R₅, and R₆ areoptionally linked; wherein X is selected from the group consisting ofBR, NR, PR, O, S, Se, C═O, S═O, SO₂, CRR′, SiRR′, and GeRR′; and whereinm is 1 or
 2. 17. The first device of claim 16, wherein the first deviceis a consumer product.
 18. The first device of claim 16, wherein thefirst device is an organic light-emitting device.
 19. The first deviceof claim 16, wherein the first device comprises a lighting panel. 20.The first device of claim 16, wherein the organic layer is an emissivelayer and the compound is an emissive dopant.
 21. The first device ofclaim 16, wherein the organic layer is an emissive layer and thecompound is a non-emissive dopant.
 22. The first device of claim 16,wherein the organic layer further comprises a host.
 23. The first deviceof claim 22, wherein the host comprises a triphenylene containingbenzo-fused thiophene or benzo-fused furan; wherein any substituent inthe host is an unfused substituent independently selected from the groupconsisting of C_(n)H_(2n+1), OC_(n)H_(2n+1), OAr₁, N(C_(n)H_(2n+1))₂,N(Ar₁)(Ar₂), CH═CH—C_(n)H_(2n+1), C≡CHC_(n)H_(2n+1), Ar₁, Ar₁—Ar₂,C_(n)H_(2n)—Ar₁, or no substitution; wherein n is from 1 to 10; andwherein Ar₁ and Ar₂ are independently selected from the group consistingof benzene, biphenyl, naphthalene, triphenylene, carbazole, andheteroaromatic analogs thereof.
 24. The first device of claim 23,wherein the host comprises one or more compounds having the formula:

wherein p is 0 or
 1. 25. The first device of claim 22, wherein the hostis selected from the group consisting of:

and combinations thereof.
 26. The first device of claim 22, wherein thehost comprises a metal complex.